Method of separating calcium from magnesium contained in saline solutions.



-1 m smarns PATENT WQE 1 CHARLES GLASER, or BALTIMORE, MARiYLANDL z 3 METHOD or :SEPARATING C LCIUM FnoM MAGNESIUM CONTAINED 'I1\T sAnIuE SOLUTIONS.

1,242,434 ,7 Specification of Letters Patent, P t te get, 9,1917. No Drawing. Application filed October 8, 1914. Serial No. 865,742. A

To all whom it may concern? Be it known that 1, CHARLES GnAsnR, a citizen of the United St2tt6S,'itI1d'IGSlClGnt of Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Methods of Separating-Calcium from Magnesium Contained in Saline Solutions, of which the following'is a specification. The present invention constitutes a further' improvement upon-the processr described i'n'U. S. Patents N0.-'9 57,416 and No.

957 ,417 both of Ma )10, 1910 and 'Reissue Patent No. 13268 0 July "11, 1911 and resides in a method of separating calcium from magnesium contained in saline solutions'. I

' The present methodhas beenconsiderably simplified and is carried out in the following manner:

The brine or other saline solution, con

taining calcium and magnesium salts preferably as'chlorids, is heated to a temperature of not higher than 0., and enough of a solution of sodium carbonate is aidded to convert all calciuman'd magnesium salts into carbonates. At and below the temperature stated,however, onlycalcium will be precipitated as carbonate. After removal of this precipitate, preferably by drawing the clear supernatant solution into another vessel, the temperature of the solution is increased to about 72 0., when the magnesia will commence to separate out. The heating is continued and, when a temperature of85 G. is reached, it will be found, that the largest part of the magnesia has separated out. As a matter of practical safety, it is advisable, however, tocontinue heating until the temperature of the boiling point is reached, at which the liquid is kept for a short time.

The removal of magnesia is so complete, that its presence can no longer be proven by ordinary analytical methods.

The improved method here described is of very great practical importance, as no observations are necessary to find the instant when enough sodium carbonate solution has been added to precipitate only the calcium and not the magnesia. This is done automatically, as at the stated temperature magnesium carbonate is quite soluble in brines. The entire sodium carbonate solution may therefore be added in one operation, which makes a great saving of time for the workmen and leaves nothing to their judgment. l/Vhenthe magnesia content in the brine is very low, less than 0.041% for instance, it

sometimes happens, that upon heating the brine to-higher temperature, magnesium carbonate does not completely, or not at all precipitate, unless a restricted quantity of alkali, such'as sodium hydroxid solution, is i added to favor the'formationof a basic mag nesium carbonate. '1-

' Below is given one example. of how@ this method may be carried .out:

Supposing the brine used, originally con tamed 1825 pounds of calcium oXid and 2268 pounds magnesia in 300 tons of the l1qu1d.. Of the calcium oXid present 167 pounds have been previously removed in the discard as carbonate, leaving 3095.5 pounds of calcium carbonate to be recovered. 300 tons, equal to 62500 gallons of this brine, previously-treated for the separation of the dis-'- card and sulfate-ions, as '1 described in the abovecited patents, is nowplaced in 'a tank 7 and heated, ifnecessary, to a suitabletemperature under continuous stirring, where-' upon 4:298 gallons 10%soda-solutionis added. Of this sodium carbonate solution the calcium requires 3615 gallons,'-whi'le the mag-' nesia only requires 683 gallons.

1. A method of separating calcium from saline solutions, containing calcium and magnesium, consisting in adding to the said solution, a quantity of sodium carbonate solution sufficient to change the calcium salts and the magnesium'salts into carbonates, and maintaining the liquid at a temperature not exceeding 60 C.,.thus causing only the calcium carbonate to precipitate. v

2. A method for separating calcium and magnesium from a saline solution, containing calcium and magnesium consisting in adding to said solution, a quantity of sodium carbonate sufiici'entto change boththe calcium salts and the magnesium salts into carbonates, agitating the liquid lt'or a suliicient timeto secure homogeneity and allowing it to rest, until the calcium carbonate is precipitated as an amorphous powder; and thereafter heating the separated supernatant solution to a -temperature ranging from 70 to 103 (1. and causing the magnesium to precipitate as a carbonate.

3.. A manna of separating calcium and magnesium from a saline solution containing calcium and magnesium, consisting in adding to said solution, a quantity of sodium carbonate solution suflicient to change both the calcium salts and the magnesium salts into carbonates, maintaining the liquid at a temperature not exceeding 60 10,, until the calcium carbonate precipitates, then separating such precipitate from the maining liquid"; and thereafter heating the remaining liquid to a temperature ranging from 70 to 103 0., and causing the nesium to. precipitate as a carbonate.

4. A method of separating calcium and magnesium from saline solutions, containing calcium and magnesium, which consists in adding to such solution a quantity of sodium carbonate solution sufiicient to change the calcium salts and the magnesium salts int-o1 carbonates, then bringing the Liquid to a temperature not over 60 G., and so maintaining it until the calcium precipitates as carbonate; then adding caustic soda to the remaining liquid and raising the temperature thereof to from 70 to 103 0., and so w res of miste eat m be time n? maintaining it until the magnesium is precipitated" as a slightly basic carbonate.

5. A method of separating calcium and magnesium from saline solutions, containing calcium and magnesium, consisting in adding to such a solution, While at a'moderate temperature not exceeding 60 (1., a quantity of sodium carbonate solution sulficient to change the calcium salts and the anagnesiui-n salts bo -l into carbonates, maintainingthe liquid at such temperature until the calcium carbonate has precipitated; then adding a small quantity of caustic soda to the remaining liquid and heating it to a temperature at which the magnesium c rbonate coag lates and thereby causing the magnesium to precipitate as a slightly basic carbonate.

6.. The art of recovering magnesi m om saline solutions containing both calcium and magnesium Which consists in mixing with such solu i n .su ficien f a solub e, ca ona e t c n ert. th th calcium and a nesium into ca bonates e ta li h te r perature a hich the nre ted calc m ipitates, separating th rema n g s lutio with its c nvert d magnes um a herei-v rai in the temper ture to th a Which the converted magnesium precipitates, and then separating the precipitated magn sium carbonate.

The foregoing specification signed at Bah timor Ma, t is'fif enth day at tember, 1914. t v I a Y Y HAB ES GLASER, I presence of two Wi ness s: V

a STANLEXQARVSWELH r sa t a h. b as esse ts ,e eisi ee 9 was rename- 

